On the contrary I can say first hand that it is true (3700X which is two years newer, but on benchamrks it is a toss up between the two). What modern GPU at you using?
3700X's 8-cores is a generational leap above the 7700k's quad core for modern games. They aren't comparable at all.
I ran a GTX 1080 and then an RTX 3080. The performance was not very good in modern games designed for current gen consoles like pretty much any BR game for example. Some games got high FPS at times but with low minimum FPS.
